ADDRESS

Faculty of Engineering and Built Environment
Universiti Kebangsaan Malaysia

Volume 29(2) 2017

Table of contents

 

No. Article Page  
1. Effect of Chemical Treatments and Coupling Agents on the Properties of Unidirectional Jute Fiber Reinforced Polypropylene Composite

Subashis Kumar Roy, G. M. Arifuzzaman Khan, M. Ahsanul Haque, Md. Shamsul Alam
Abstract

Due to different chemical nature of jute and polypropylene, their blended composite materials often show failures behavior when applied in load bearing purposes. The aim of the research is to improve the properties of unidirectional jute fiber (JF) reinforced polypropylene (PP) composite. Unidirectional fiber composite was produced by simple hot press molding method according to weight percentage of 30wt% filler (JF), 2wt% coupling agent (compatibilizer) degraded PP (DgPP) and maleated PP (MAPP) and 68 wt% matrix (PP). To improve the interfacial interactions between the fiber and PP, the fiber was chemically modified with 10w/v% NaOH, 6w/v% dicumylperoxide (DCPO), 0.05 w/v% K2Cr2O7 and 5 w/v% H2O2 solution. The water absorption, tensile and thermal properties of raw and surface treated fibers composites were compared in particular coupling agent. It has found that the fiber treatments and addition of coupling agents, composites showed better properties. Among the composites, 10 wt/v% NaOH treated jute reinforced PP composite by using MAPP compatibilizer was presented better water absorption and mechanical properties. The positive change of the treated fiber composites was also found in case of the thermal stability that investigated by the TG, DTA and DTG tests.

 

Keywords:  Jute fiber (filler); polypropylene (matrix); composites; coupling agents; properties

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-01
63 – 70
2. Physical Properties of Halloysite Nanotubes-Polyvinyl Alcohol Nanocomposites using Malonic Acid Crosslinked

Tayser Sumer Gaaz* & Emad Kamil Hussein
Abstract

Halloysite nanotubes (HNTs) based nanocomposites were produced by blending individualized HNTs dispersion with polyvinyl alcohol (PVA). Several sequential separation techniques were applied to obtain stable individualized HNTs dispersion. The preparation of PVA-crosslinked-HNTs nanocomposite has not been developed and, to the best of our knowledge, there was no published report indicating the use of neither dispersion nor crosslinker agent. In addition, PVA was crosslinked using the crosslinker malonic acid (MA) and sulfuric acid as a catalyst. This individualization increases the mechanical and thermal properties of HNTs-PVA nanocomposites. As a side result, crosslinking was employed to make PVA water-insoluble and hence to become more useful in biomedical applications. Examination of the nanocomposites indicated that HNTs were uniformly dispersed in both PVA as well as crosslinked PVA. These nanocomposites could be composted easily and hence would be good candidates to\replace some of today’s traditional non-biodegradable plastics that end up in landfills.

Keywords: Nanostructures; Polymer Nanocomposites; Thermal Properties; Nanocomposites

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-02
71 – 77
3. Optimization of Internal Mixing Parameter on the Electrical Conductivity of Multiwall Carbon Nanotubes/Synthetic Graphite/Epoxy Nanocomposites for Conductive Polymer Composites Using Taguchi Method

Irmayani* & Hendra Suherman
Abstract

Conductive polymer composites (CPCs) can be widely uses as electronic devices, artificial muscles, solar energy conversion, and sensors. Nevertheless, CPCs has a low electrical conductivity. Therefore this study focused to improved the electrical conductivity of CPCs by optimizing the internal mixing parameter using Taguchi Method. Multiwall carbon nanotubes (MWCNTs) as secondary filler and synthetic graphite (SG) as primary filler use in this study. The CPCs composition are; 5wt% MWCNTs; 75wt% SG; 20wt% epoxy resin as matrix. The internal mixing parameter applied as control factor in Taguchi Method analysis are mixing time, mixing temperature, and mixing rotation. Experiment was carried out based on orthogonal array design using these three internal mixing parameter. The results were analyzed using the signal to noise ratio (S/N) and analysis of variance (ANOVA). The percent contribution of each internal mixing parameters to the electrical conductivity of MWCNTs/ SG/ epoxy resin were mixing rotation (44 %), mixing temperature (26 %) and mixing time (18 %). This was managed to reduce the number of voids and nano size particles conductive filler material (MWCNTs) more evenly dispersed in the epoxy resin. The optimum internal mixing parameters used to produce MWCNTs/SG/epoxy nanocomposites was effective to increase the electrical conductivity becomes 197 S/cm.

Keywords : Internal Mixing Parameters; Electrical Conductivity; Taguchi Method; Analysis of Variance (ANOVA)

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-03
79 – 85
4. Built Form Properties as Sign and Symbols of Patron Political Ideology

Alice Sabrina Ismail* & Erna Nuralia Zhaharin
Abstract

This paper discusses on the study of architecture as a sign system by analyzing its generic elements-form making based on the Western philosophers. In addition, this study investigates how built form act as a sign and contribute to major symbolic content which gives concrete expression to the socio cultural and political phenomenon. In this case, prominent buildings found in the modern context are used as examples to explain how they are capable of communicating the intentions of patrons to users as well as transmitting messages when users invest the building with meaning. This is important as built form do not only symbolize norms of society and social structure as well that relative to world view, hierarchies and the like. This paper is significant as it develops a systematic approach to understand the relationship between sign symbols and material culture. This understanding makes substantive contribution to elucidate the production of meaning in relation to the built environment across different cultural settings. Furthermore, it provides an insight that the meaning of the built environment is dependent on human intentions and purposes as conceived in a particular cultural context like Malaysia and the global scene. Therefore, it provides a clear framework to lead architectural scholars, designers and researchers, who are interested in analysing the themed environments, towards a better understanding of the structural relationship that exists between the built environment and social culture in contemporary society.

Keywords: Politics and Architecture; Material Culture; Built Form; Architecture Sign and Symbol

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-04
87 – 96
5. Development of Roundabout Delay Models Using Traffic Simulation Programs: A Case Study at Al-Mansour City, Iraq

Alla Jaber Essa, Amiruddin Ismail, Ali Emad Jehad, Ameer Abdul Adheem Hussein, Abdullah Hayal Khalaf & Hussin A.M. Yahia
Abstract

Due to the increased number of vehicles, shopping centers and rapid growth population of Al-Mansour city, daily trips have been increasing besides generating traffic congestion in major roundabouts in the city. Those will make developing an imperial delay model in roundabouts important due to the traffic and geometric influences. Therefore, two major roundabouts have been selected in the city to be taken as a case study. Geometric features for the selected roundabouts have been measured accurately by satellite images via ArcGIS. Traffic and geometric data analysis indicate that both are significantly important on delay models. The delay time produced by SIDRA and SYNCHRO has been compared with the delay time measured from the field. A significant difference in delay for roundabouts is noticed. This difference could be attributed to the difference in driver behaviour. Ideal saturation flow is the main factor related to driver behaviour, so it adjusted to be the average of the saturation flow measured from the field (2200 vphgpl).

Keywords: Traffic Delay Mode; Roundabout; SIDRA; SYNCHRO; Linear Regression Model.

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-05
97 – 103
6. Fermentable Sugars from Agrowastes using Cellulase Enzymes from Local White Rot Fungi Pycnoporus sanguineus

Norhazmiza Ahmad Safri, Rafidah Jalil & Mohd Sahaid Kalil*
Abstract

The viability of fermentation process is very much depends on the use of a cheap carbon source from lignocellulosic materials. It needs to hydrolyse into simple and readily metabolize carbohydrate using cellulase enzyme. Pycnoporus sanguineus has been able to produce cellulase enzyme with high enzyme activity that can convert lignocellulosic materials into fermentable sugar. P. sanguineus was culture using α-cellulose as carbon source for enzyme production via submerged fermentation (SMF) at different agitation speeds (100 and 150 rpm). Crude cellulase enzyme extracted from fermentation broth by centrifugation was used in hydrolysis of sawdust and sugarcane bagasse at different substrate concentrations (1 – 5% w/v). It was found that crude cellulase enzyme contain three main enzymes components i.e. endoglucanase, exoglucanase and xylanase with maximum activity of 1.55, 0.45 and 8.0 U/mL respectively that achieved after four days of cultivation at agitation speed of 150 rpm. The most suitable temperature and substrate concentration for sawdust and sugarcane bagasse hydrolysis by cellulase from P. sanguineus was at 30 °C and 5 % (w/v) where sugarcane bagasse produced maximum of 59.10 g/L fermentable sugar as compared to from sawdust (58.84 g/L). Fermentable sugar productivity was the highest (2.45 g/L/h) when sawdust was use compared to 0.50 g/L/h for sugarcane bagasse. Fermentable sugar produced from agrowastes using cellulase enzymes of P. sanguineus has highest potential as a feedstock for biofuels and biochemicals production.

Keywords: Lignocellulosic Biomass; Cellulose; Fermentable sugars; Pycnoporus sanguineus

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-06
105 – 111
7. Measurement of Gas Hold­up and Mass Transfer in a Bubble Column by using Electrical Resistance Tomography (ERT)

Nur Tantiyani Ali Othman* & Nur Syamimi Wahid

Abstract

Gas dispersion performance and gas hold-up in a bubble column was investigated by using electrical resistance tomography (ERT). Experiments were carried out to visualize flow pattern and gas hold-up at different gas velocity, type of impeller and speed of impeller. In this study, cylindrical bubble-column with a diameter of 13.5 cm and a height of 97.5 cm, made of glass that was mounted with four planes of 16 stainless steel electrodes are connected to an ITS P2000 ERT system. The column was equipped with perforated plate consisting of five holes and each has internal diameter of 3.0 mm. The effect of four parameters; gas flowrate, speed of impeller, 2 types of impeller; Rushton and Lightnin impeller, and three types of gas; oxygen, hydrogen and nitrogen gas on the gas dispersion performance in the bubble column were investigated. It was observed that the gas dispersion rate is increased with increasing gas density where the oxygen gas has the highest of dispersion gas rate as compared to the others gas. The gas hold-up was determined from the correlation method to estimate the transition velocity and dispersion of gas in a bubble column. The results showed that with increasing of the superficial gas velocity, the total gas hold-up increases. Besides, the gas hold-up increased due to decreasing of gas density. It can be concluding that the optimum mixing condition was obtained by using Lightnin A320 impeller with the speed rate at 250 rpm.

Keywords: Gas Hold Up; Electrical Resistance Tomography; Gas Dispersion; Bubble Column

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-07
113 – 119
8. Polyaniline Composite Membranes Synthesis in Presence of Various Acid Dopants for Pressure Filtration

Rosiah Rohani*, Izzati Izni Yusoff, Farah Adlyna Mey Efdi & Mohd Usman Mohd Junaidi & Asif Ali Qaiser 
Abstract

Polyaniline is a conductive polymer that is recently used as a material in producing a pressure filtration membrane. Polyaniline can be doped in various acids as dopants of different sizes and shapes to modify its inherent properties to produce membrane with high flux and rejection. This work is aimed to fabricate polyaniline composite membrane in presence of different acids as dopants namely hydrochloric acid, maleic acid, poly(methyl vinylether) acid (PMVEA) and polyacrylic acid (PAA). This polyaniline was coated onto microporous polyvinylidene fluoride (PVDF) support by using a specially fabricated two compartment cell. The field emission scanning electron microscope (FESEM) results show that the morphology of the coated polyaniline on PVDF membrane support is in globular shapes, which elongates at different sizes depending to the acid used. From the thermal analysis, the melting point of polyaniline coated PVDF membrane remains at 260 °C, similar as obtained in the pristine microporous PVDF indicating no thermal change upon polyaniline coating. From all membranes prepared, the doped polyaniline membrane possessed a good conductivity value except for polyaniline-PMVEA membrane, which has the lowest value. In terms of the membrane filtration performance, which was measured based on the flux of pure water and polyethylene glycol (PEG) rejection, polyaniline-PMVEA membrane has a high flux and the highest PEG rejection. This result indicates that the conductivity does not influence much on the membrane filtration performance, but rather due to the physical coating itself. Different acid dopants present during polyaniline coating will lead to different filtration performance.

Keywords: Polyaniline; Composite Membrane; Chemical Polymerization; Acid Dopant; Pressure Filtration

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-08
121 – 130
9. Application of Membrane Technology towards The Reusability of Lake Water, Mine Water, and Tube Well Water

Y.H. Teow*, M.S.H. Ghani, W.N.A. Wan Mohammad Hamdan, N.A. Rosnan, N.I. Mohamad Mazuki & K.C. Ho
Abstract

Severe water shortage caused by El-Nino has caused life-threatening drought conditions globally. This natural disaster has put millions of lives at risk and forcing the people to search for waster. However, the water scarcity problem was not just limited to the countries that were strike by El-Nino. Poor water management and climate change were bringing droughts to Asia and the Pacific. The water scarcity worldwide has recently reached the alarming rate and received the greatest attention among the people. Membrane technology is an innovative technology which has proven to be effective and efficient for water and wastewater treatment. Therefore, membrane technology has high potential to be employed for the treatment of lake water, mine water, and tube well water in increasing the fresh water production for reuse purpose. The objective of this work is to investigate the potential of membrane technology for treating the lake water, mine water, and tube well water. A laboratory bench-scale dead-end test rig was used in this study to evaluate the performance of commercial flat-sheet nanofiltration (NF) – NF270 and reverse osmosis (RO) – BW30 membranes. Both source water and treated water were analysed based on chemical oxygen demand (COD), ammonia nitrogen (NH3-N), colour, total suspended solid (TSS), pH, and temperature. In order to prove the reuse concept of membrane technology, the permeate water quality after the membrane filtration process was compared with National Water Quality Standard (NWQS) of Malaysia. The results from this study shown that the permeate water filtered by NF270 and BW30 membranes were able to meet the NWQS Class III, which was suitable to recycled for livestock drinking and irrigation purposes.

Keywords: Lake water; Mine water; Tube well water; Membrane technology; Water reuse

DOI : dx.doi.org/10.17576/jkukm-2017-29(2)-09
131 – 137